docs: def _insert_breaklines(self):
      """Inserts a breakline instead of a trailing space if the chunk is in CJK.
      """
      target_chunks = ChunkList()
      for chunk in self:
        if chunk.word[-1] == ' ' and chunk.has_cjk():
          chunk.word = chunk.word[:-1]
          target_chunks.append(chunk)
          target_chunks.append(chunk.breakline())
        else:
          target_chunks.append(chunk)
      self.list = target_chunks